The present invention relates to a method for disinfecting a given facility or equipment such as a room, apparatus, container or vehicle, and a mobile disinfection unit for use in the method.
It is well known that facilities of different kind such as rooms, containers or vehicles can be infected or contaminated with different chemicals, spores or viruses. These infections or contaminants are detrimental to the health and the quality of life. So far the technology is mainly based on manual cleaning, which is time consuming and expensive and which further contains the risk of cross contamination during the cleaning period.
Several attempts have been made in order to meet this problem, however presently, there is not an integrated system available for cleaning and disinfecting hospital rooms, where also nanoparticles can be removed to a high extend. Nanoparticles are present in all environments, and are also likely to be formed from different gases in the air after being oxidized by ozone. Terpines for example form nanoparticles when oxidized, and many are cancerogenic. Also, in hospitals and anesthesia many of the inhaled gases and its residuals contain components harmful for the health and environment.
UV light is used in hospitals to sterilize the air, but the method only removes very few specific types of pollution, and furthermore does not create enough radiation to remove bacteria and spores within an acceptable time. Chemical treatment is hazardous for the personnel and by mechanical filtration the pollution particles are only collected on a screen.
Mechanical filtration is equal to high pressure loss. The filter must be changed and can itself become a source of bacterial contamination. In contrast electrostatic filtration does not cause a large pressure drop, and removes pre-existing particles. Electrostatic filtration does, however, not act on gas-phase pollution.
Ozone in combination with humidity is known to have a rapid effect on spores, viruses and bacteria. Ozone is further one of the strongest oxidizing agents known to mankind. During ozone treatment a lot of the substances in air are being oxidized resulting in nanoparticle byproducts directly able to penetrate the respiratory system, or to have health or environmental effects.
To remedy the above disadvantages different modifications and variations of disinfection and sterilization methods have been proposed. Examples include the methods and apparatuses of Steritrox Limited in the patent application GB2468641 and the U.S. Pat. No. 7,604,774. The sterilization method presented in GB2468641 aim at sterilization, decontamination and/or sanitation of a cool environment e.g. a food preparation area. The method describes the steps of measuring the temperature of an enclosed environment to be treated, calculating the relative humidity, introducing humidity to the environment, introducing ozone to the humidified environment, maintaining a predetermined concentration of ozone in the environment, and finally removing the ozone from the environment again after the aimed degree of sterilization has been obtained. In case removal of the ozone takes too much time, the ozone level may be reduced by introducing a hydrocarbon gas containing a carbon-carbon double bond into the environment. The sterilization method presented by Steritrox Limited in U.S. Pat. No. 7,604,774 is much similar to GB2468641, however comprising the step of introducing an aromatic hydrocarbon into the humidified environment after introducing ozone to preferentially react with said discharged ozone to form hydroxyl radicals. The Steritrox documents do thus not let the apparatus collect the produced contaminants and decompose the contaminants in a filter. Furthermore, in the U.S. Pat. No. 7,604,774 the apparatus does not collect and decompose the residual ozone in a catalyst. Also, it is not considered how to remove toxic gaseous contaminants and particles such as smoke and dust from the air.
WO 2008/014615 A1 discloses a method of sterilizing a closed environment such as hotels, airplanes, cruise ships and hospitals, and a disinfection apparatus to be used in the method. The method of sterilization is among others aimed against SARS, influenza virus, poliovirus and rhinovirus. The method comprises the steps of placing the disinfection apparatus in the closed environment, having the apparatus generate ozone in the closed environment to a predetermined ozone concentration, rapidly increasing the humidity in the closed environment to a predetermined level, and guiding the air in the closed environment through a catalytic converter so that the ozone concentration is reduced to a predetermined safe level, at which stage the disinfection apparatus signals that the closed environment is safe to enter. The predetermined ozone concentration is stated to be within 15 to 40 ppm, or 20 to 30 ppm, and may be depleted with a catalytic converter and by guiding ozonated air through a manganese dioxide and activated carbon tray. The humidity in said closed environment may be raised to levels higher than 90% by use of an ultrasonic humidifier. The disinfection apparatus may further comprise e.g. an ozone sensor, and a first fan to guide ozonated air into the catalytic converter. However, WO 2008/014615 A1 does only provide one inlet tube, so that intake of air to the apparatus happens through the same inlet tube during both the initial introduction of ozone to the environment and the final reduction of ozone. The processes cannot be separated, which complicates the design of the apparatus and wears more on the apparatus. GB 2 472 509 A and US 2009/010801 A1 also present air cleaners comprising more than one means of cleaning such as an ozone depletion unit, VOC filter and electrostatic filter. They do, however, not provide an alternative design in regard to the inlet tube, but also only have one inlet tube.
Known methods for sterilizing/disinfecting a given facility thus result in an incomplete and complicated process. Thus, improvements over the prior art are desired.